Apparatus for silvering



March 11 1924..

C. H. RUDER ET AL APPARATUS FOR SILVERING Original Filed Aug. 19. 1922 Patented Mar. ii, i924.

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CHARLES H. RUDER AND GEORGE M. D. SHADWICK, 0F SAN FRANCISCO, GALL'IEDENIAu APPARATUS FOB, SILVERING.

Application led August 19, 1922, Serial No. 583,000. Renewed January 14, 1924.`

To all Iwho/m 'it may concern:

Be it known that we, CHARLES H. RUDER and GEORGE M. D. SHADWICK, citizens of the United States, and residents of the city and f. county of San Francisco, State of California, have invented a new and useful Apparatus for Silvering, of which the following is a specification.

Our invention has for its object the depositing on a portion of the surface of an incandescent lamp bulb a `metallic reflecting surface, rWhich will be hard and durable and free from injury such as heat and exposure when the lamp is in service.

Other-objects will appear from the speci-A fieations which follow.

These objects we accomplish by mounting the lamp with the filament portion down-v ward with respect to the silvering solution during the period that the depositis being made upon the lamp surface. The silveringwe accomplish by applying a small quantity of solution adjacent the glass surface of the lamp where the deposit is to be made, said solution being contained within a cup of hard rubber or other inert material. formed of suitable shape and having a soft gasket in the lower portion into which the lamp is tted, thereby sealing the bottom ot1 the cup against leakage of the solution. The solution-is then poured around the lamp and the filament energized by an electric current whereby the glass surface of the lamp and the adjacent solution is heated. Y

'We atta -h special importance to the position of the lament being downward with respect to the solution, thereby maintaining the solution during` the depositing perio' adjacent tothe hottest portion of the lamp and' securing an advantageous circulation of the solutionv which ,results in a maximum amount of closely adhering metallic der' posit on the glass surfaceinstead of on the surface of thefcup or container.` a

By referring to the accompanying drawing our. invention will be madeelear.

Fig. '1 illustrates a lamp in position in the cup 'or container which latter isshown in cross section. and as positioned duringtheperiod of treatment and also shows the electrical connections from the swinging arm ,which We employ for eenteringand energiz ing the lamp. i L l Fig. 2 is a view of the apparatus of Fig. 1 and at right angles thereto.'

Fig. 3 is one of our completed lamps showing the manner in which light is distributed upward by the frosted surface between the lower limit of the silvered surface 19 and the equator 21.

Throughout the figures similar numerals refer to identical parts.

The lamp which is to be silvered is indicated by the numeral 1. Its spherical portion is pressed into place against the soft gasket 2 forming the bottom portion of the cup 3. The silvering solution 4 is then poured around the lamp to the desired depth 5 and the arm 6 swun from its dotted to the full line position, an the electric circuit is completed through the spring member 7 and the latch member 8, these forming the two terminals from any conventional source of electrical energy furnished through the double cord 9 and socket 10. The cup 3 is carried `on any suitable support 11 which may be arranged toreceive a 'plurality of cups, for. each of which there is a swinging arm 6. The lamp bulb projects through an opening 12 in the support 11 and its ilament 13 projects downward to or .below the zone of silvering 14. l

' At 15 and 16 are indicated conventional' hinges and wall support.

On account of the position of the filament below the silverizing zone, the greatest amount of heat is distributed from the filaposit in less timeand with greater economy y in the reagents used than'has been heretofore attained.

Before placmgkthelamp in .the cupf3 the..

glass surface' is to bey chemically cleaned and we'prefer to employ for this'a solution lconsisting of one pound bichromate of potash in 300 c. c. ofv water and 1500 c. c. of sulphuric acid into which the lamp is to be immersed about 10 seconds, then washed in running water and finally in distilled water.

The process includes the employment of a silveringv solution com edsubstantially of 'grams nitrate of silver; 5 grams sulphate of copper 2 grams sulphate of nickel, which are to be dissolved separately and then mixed. A suiicient quantity of ammonia is then added to turn the solution a deep blue, after which a saturated solution of tartaric acid is added until the solution swinging the arm 6 downward on the hinge l5 The hottest port-ion of the lamp will now be in thevzone' to 14. Y'The solution is heated thereby and the circulation within the said solution, due to the hot glass surface, takes place in the direction of the arrows 17 and' 18 causing a metallic deposit of silver, copperand nickel on the glass surface, which Will be of the requisite thickness in about one hour.

The arm 6 is then swungl up and the lampremovedvand while still moist is to be dipped in a solution of 10% mercurio cyanide, after which the lamp is rinsed in clear water and the deposit allowed to dry hard. 4

- The coating may now be trimmed as to the line 19 to remove the feather edge and if desired the lamp ymay be frosted over the unsilvered portion of its spherical surface 2O up to the line .19. We prefer to carry this frosting substantially 10 degrees above the equatorial portion 21 of the bulb so that when the lamp is in a depending position in a fixture the diffused illumination secured from the surface above the equatorial por- .tion and up to the line 19 diffuses upward a suicient illumination to reduce shadows on the fixture or ceiling 23 to a minimum.

This result is best shown in Fig. 3 wherein the equatorial line of the spherical surface is shown at 21 above which the frosted surface extending to 19 forms a source of illumination'indicated,by the rays as 22, which falling upon'the ceiling 23 reduces shadows thereon -to a minimum.

`We claim: y

1. Apparatus for silvering an incandescent lamp consisting of a cup provided with an open bottom having a soft gasket adapted to snugly hold the equatorial portion of an incandescent lamp and 4leaving a portion o-f the glass surface exposed within the cup vand above the lamp filament.

2. Apparatus for silvering an incandes cent lamp consisting of a cup provided with: -an open bottom having a soft ved to snugly hold the equatorial portion of gasket adaptan incandescent lamp and leaving` a portion of the glass surface exposed within the cup and above the lamp filament, and contacts adapted to engage and energize the lamp. u

3. 'Apparatus for silvering an incandescent lamp consisting of a cup provided with an open bottom having a soft gasket adaptmovable ed to snugly hold the vequatorial portion of an incandescent lamp and leaving a portion of-the glass surface exposed within the cup. .and above the lamp filament, and movable contactsl adapted to engage and energize the lamp, said contacts carried on aswinging- CHARLES H. RUDER. encuen M. D. sHADwicK 

